So, I've had a weeks home audition with the Rega RS1's
Very detailed, smooth, warm - and various other superlatives.
The tweeter gives very detailed highs without becoming harsh or bright (I've read that on the R1's this was a concern).
The mids are superbly clear and rich. Having the tweeter below the mid/bass seemed an unusual configuration but they integrate seamlessly.
My only slight (very slight) concern would be the bass. Having read a review on a rival site which stated that the RS1's were lightweight in the bass - I certainly found the opposite to be true. The bass was tight, detailed and kicked low. However, on heavy electronic music there was a slight bit of boom. This may well be due to positioning and/or room accoustics - they are positioned in an alcove on Atacama stands about 7ft apart and about 8" from the rear and side walls (although the side walls only extend about 2ft alongside the speakers).
With my preferences for Jazz, Vocal, Soul and classical music I found them to be spot on! Vinyl was especially lush!
However, with heavy rock/electronic music I found the soundstage a bit muddled - not quite so clear in picking out the individual instruments - again this could be due to placement and the slight boom of the bass may be muddying the mids.
They are not very forgiving of poor quality recordings but I guess with speakers of this standard why would you want anything less.
I'm no expert but that's my overall view (for what its worth). Overall they are stunning speakers!
Are these the speakers for me? Yes!
Although.....the EB1's might be worth .... arrrrrrgh!!!